1968 6HP Johnson driveshaft pin - help needed!

Swell

Petty Officer 3rd Class
Joined
Aug 8, 2010
Messages
98
I have found something very unusual with my recently purchased 1968 6hp Johnson (CDL-25c). There's no pin and no hole to take a pin near the top of the driveshaft, the one which compresses the various components of the crankcase seal. This means it's been running with little or no seal. Could it be that someone's fitted a driveshaft from an older model? I understand that they used to have a different setup and the slotted ledge / pin assembly was only added after a certain year.

I'm keen to rectify this and aim to drill a hole and fit a stainless roll pin, but I need to know where the pin needs to be located relative to the driveshaft - and also approximately what diameter of hole is needed? I've done some working out from the drawings on the BRP website and from the service manual, but not sure if these are to scale and they also look to be from an offset angle. However I've worked out the distance between the impeller pin and the top pin to be about 371 mm. This might be close enough given that all the pin needs to do is compress the spring which forms the seal (+/- 1 or 2 mm maybe ok??), but an actual measurement is what's really needed! If anyone can help me with this it would be very much appreciated!

Many thanks,

Roger

PS This topic was mentioned in a previous post about a cooling problem, but as this is a separate issue and quite a big one I thought it made sense to create a new thread so as to highlight the issue.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: 1968 6HP Johnson driveshaft pin - help needed!

Unusual indeed. I can't think of any case where they didn't use a pin. Unless it is from a fairly recent motor. Anyhoo, I measured an older than yours model and the center of the pin is 2-3/8" down from the top end of the shaft. It is a 3/32" hole.
 

Swell

Petty Officer 3rd Class
Joined
Aug 8, 2010
Messages
98
Re: 1968 6HP Johnson driveshaft pin - help needed!

Fitted the driveshaft pin (2.4mm stainless roll pin into a 2.5mm hole, 19mm long) 60mm from the end of the driveshaft. Went into the crankcase ok so have to assume it's doing what it should be doing.

Will try engine on the water tomorrow - can't wait!

Thanks for all the help.

Roger
 
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